Door opening and closing mechanism for a refrigerator having revolving shelves

ABSTRACT

A door opening and closing mechanism for a refrigerator having revolving shelves in which a single motor is used for revolving the shelves and novel means is provided for disconnecting the shelf rotating means from the motor and for connecting it to door opening and closing means when it is desired to gain access to the interior of the refrigerator. The shelving may be manually rotated when the door is open to permit one or more items on the shelves to be removed and/or other items added. The novel means also includes auxiliary means for forcing the door into an airtight closing position at the end of the closing movement of the door to keep the refrigerator door hermetically sealed. The closing of the door will automatically connect the shelf-rotating means to the motor for again causing the shelves to rotate.

United States Patent 3,512,859 5/1970 Barroero...........

Primary Examiner-James C. Mitchell Armrneywilliam R. Piper Earl l-loey [72] lnventor 31763 Shadysprlng Road, San Francisco,

Calif. 94546 [21] Appl. No. 17,381 [22] Filed Mar. 9, 1970 [45] Patented 1971 ABSTRACT: A door opening and closing mechanism for a refrigerator having revolving shelves in which a sin gle motor is I 54] DOOR OPENING AND CLOSING MECHANISM :sed for retvolvlkng tkllreushelves and now; meagls rs pr'ovrdeg :or FOR A REFRIGERATOR HAVING REVOLVING rsconnec mg t e s e re a ng means rom e mo or an or connecting It to door opening and closing means when it IS desired to gain access to the interior of the refrigerator. The shelving may be manually rotated when the door is open to permit one or more items on the shelves to be removed and/or other items added. The novel means also includes auxiliary means for forcing the door into an airtight closing position at the end of the closing movement of the door to keep the refrigerator door hermetically sealed. The closing of the door will automatically connect the shelf-rotating means to the motor for again causing the shelves to rotate.

PATENTEU 05m 4 ISTI SHEET 1 [IF 3 INVENTOR. EARL HQEY w Z .7 ATTORNEY PATENTEU DEE I 41911 SHEET 2 0F 3 INVENTOR. EARL HOEY WM 7F. 92

ATTORNEY PATENTEU DEC 1 41% SHEET 3 BF 3 ATTORNEY DOOR OPENING AND CLOSING MECHANISM FOR A REFRIGERATOR HAVING REVOLVING SHELVES BACKGROUND OF THE INVENTION Where display refrigerators are used in stores, one motor is generally employed for continuously rotating the shelving within the refrigerator so long as the refrigerator door is closed in order to display the items on the shelves. Another motor is used for opening and closing the refrigerator door. The door, when closed, may not provide a hermetically tight seal. Also, the shelves will be continuously rotated even when the door is opened and this will make it difficult to remove one or more items from the shelves and/or add other items thereto.

I have invented a novel mechanism whereby only one motor is needed for rotating the circular shelves and also for opening and closing the refrigerator door, this same mechanism automatically disconnecting the shelf rotating means from the motor while the door is open so that the shelves will stop rotating but they are free to be rotated by hand so as to bring any desired item on the shelf into a position to be removed through the door opening.

SUMMARY OF THE INVENTION An object of my invention is to provide a relatively simple mechanism in which a single motor not only continuously rotates the shelving in a display refrigerator, but the same motor is used for opening and closing the refrigerator door. The mechanism also automatically disconnects the shelf rotating means from the shelves while the door is being opened and retained in the open position. This will permit the shelves to stop rotating and make it easy for a person to remove one or more items from the shelves. It is possible for a person to manually rotate the shelves while the door is open in order to bring any desired item on the shelves into a position adjacent to the door opening for permitting its ready removal. A switch may be closed for actuating the mechanism for opening the door and held closed for keeping the door open after which the switch may be opened for permitting the same mechanism to close the door and to again start the shelves to rotating for displaying the items on the shelves through a glass window in the door and/or glass windows in the display refrigerator walls. It is also possible to include an electrical time delay device that will be actuated when the switch is closed for causing the mechanism to open the door and then after the predetermined time period has elapsed, to cause the same mechanism to close the door. The switch could be a key-operated switch.

A further object of my invention is to provide a device of the type described in which novel means is provided for exerting an additional or auxiliary door closing force on the door during the final closing movement in order to force the door to make an airtight seal with the door frame and thus prevent any leakage of cold air from the display refrigerator while the door remains closed. My device should not be limited to refrigerated displays. It could be used as a locked display case and for perishable items that require chemically treated or especially controlled atmospheric conditions.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation of the display refrigerator and shows the refrigerator door with a glass panel that is substantially equal in size and shape to that of the door itself.

FIG. 2 is a side elevation of the refrigerator when looking in the direction of the arrows 22 in FIG. 1. A portion of the refrigerator and door have been broken away to show the rotatable shelves.

FIG. 3 is a top plan view of the refrigerator when looking in the direction of the arrows 3--in FIG. 1. The refrigerator door is shown arcuate in shape.

FIG. 4 is a horizontal section on a larger scale and is taken along the line 4-4 of FIG. 1. One of the rotatable circular shelves is shown in this Figure in its relation to the arcuate door. The insulation for the refrigerator walls is not shown.

FIG. 5 is another horizontal section on still a larger scale and shows the refrigerator door opening and closing mechanism with the door in closed position.

FIG. 6 is a horizontal section similar to FIG. 5 and illustrates the initial opening movement of the refrigerator door.

FIG. 7 is a horizontal section similar to FIG. 6 and shows the refrigerator door in fully open position.

FIG. 8 is a horizontal section similar to FIG. 7 and illustrates the door opening and closing mechanism with the refrigerator door in its initial closing movement.

FIG. 9 is a horizontal section similar to FIG. 8 and shows the door in almost closed position with the auxiliary door closing means being activated to aid in the final closing movement to cause the door to make an airtight seal with the door frame.

FIG. 10 is a horizontal section similar to FIG. 9 and shows the auxiliary door closing means at about the end of its operation and ready to be moved into inoperative position.

DESCRIPTION OF THE PREFERRED EMBODIMENT In carrying out my invention, I make use of a refrigerated display cabinet A, shown in all of the Figures, and this display cabinet or refrigerator has an arcuate'shaped door B. My invention pertains to the novel mechanism for opening and closing the door B. Although I have shown an arcuate door that is rotated about an axis when moving it into open and closed position, it is possible to have a flat door that can be opened and closed by sliding it in the plane of the door. FIGS. 2 and 4 show the display refrigerator provided with a plurality of circular display shelves C, all being mounted on a vertical shaft D that is rotatably supported in the refrigerator A. The parts thus far described are of standard construction and need no further description.

The door opening in the front wall I of the display refrigerator A is arcuate in shape along its top and bottom edges 2, and the opening has vertical side edges 3, see FIGS. 1, 4 and 5. A rubber-sealing strip 4 extends around all four edges of the door opening and this strip will be contacted by the door B, when the latter is closed.

I will now describe the novel mechanism for opening and closing the refrigerator door B. A baseplate E, preferably made of metal and of the shape shown in FIGS. 5 to 9 inclusive, is secured to the bottom of the refrigerator. This baseplate has a bearing, not shown, for rotatably supporting the lower end of the vertical shelf-supporting shaft D. Another bearing, now shown, rotatably supports the upper end of the vertical shaft. The circular shelves C are adjustable and keyed to the shaft so as to be rotated thereby. The axial center of the shaft is shown by the dot 6 in FIGS. 5 to 9 inclusive.

The arcuate door B is supported by a rotatable door-supporting member F and the center 5 for the arc of the door is spaced to the left of the axis 6 for the vertical shaft D, see FIG. 5. The are for the door opening 4 also has the same center 5. The member F, freely rotates about the vertical shaft D and since the center 5 for the arcuate door B is spaced to the left of the shaft axis 6 in FIG. 5 when the door is closed, a clockwise rotation of the member F and the door B for opening the door will cause the door to move inwardly and away from the doorsealing strip 4 during this do0r-opening movement. FIG. 7 shows the door B fully opened and it will be noted that the center 5 for the arc of the door has rotated to a new position with respect to the axis 6 of the vertical shaft D. The member F supports the lower edge of the door. A similar member, now shown, can support the top of the door.

This inward movement of the door as it is rotated clockwise into open position causes the arcuate-shaped door to clear the sealing strip 4 on the edges of the door opening more quickly than if the door-supporting member F rotated on the same center as the axis 6 of the shaft D. This reduces friction. The door B, in being closed will rotate counterclockwise while it is being supported by the door-supporting member F and it is only during the final short distance of this rotative movement that the door will contact with the door-opening seal 4 that extends along the edges of the door opening. It is only during this last short closing movement of the door that I provide an auxiliary door-closing force which has sufficient strength to overcome the friction developed by the door coming into contact with the sealing strip 4 that extends along the edges of the door opening.

The door-supporting member F has an arcuate slot G therein, see FIGS. 5 to 9, and the length of the slot is slightly longer than the width of the arcuate door B, that is supported by the member F. The arcuate slot has enlarged end portions 7 and 8 that are wider than the width of the slot. A pin 9, indicated by the small circle in FIGS. 5 to 9 inclusive, is carried by the baseplate E and extends upwardly therefrom. A twopiece jointed arm H has one of its pieces 10 swingably mounted on the pin 9. The other piece 11 of the articulated arm H is pivoted at 12 to the armpiece 10 so as to be able to swing with respect to the piece 10. The length of the swing of the armpiece 11 with respect to the armpiece 10 is determined by a pin 13 carried by the piece 10 and slidably received in an arcuate slot 14 provided in the piece 11. The purpose of this will be described hereinafter.

The inner piece 10 of the two-piece jointed arm H carries an electric motor as shown by the dotted circle J in FIG. 6 and the motor shaft projects up through the inner armpiece l0 and has a drive wheel K keyed thereto. When the refrigerator door B is closed as shown in FIG. 5, the drive wheel K will be received in the enlarged end portion 7 of the arcuate slot G in the door-supporting member F and it will not contact with the edge of the arcuate slot and therefore the motor can rotate the drive wheel K freely without the drive wheel imparting any rotative motion to the door-supporting member F because the drive wheel does not contact with an edge of the arcuate slot G. When the drive wheel K is in this neutral position a spring 15 that has its ends connected to the piece 11 of the jointed arm -H and to the baseplate E will yieldingly hold a seconddrive wheel L carried by the outer armpiece l l in contact with a drum M shown by a dot-dash circle in FIG. 5, this drum being keyed to the shelf-supporting shaft D. The second-drive wheel L is operatively connected to the shaft of the motor J by a belt and pulley mechanism indicated generally at 16. Therefore the motor .I will cause the drive wheel L to rotate the drum M which in turn will rotate the vertical shaft D and the shelves C. During this time the drive wheel K will rotate in its neutral position in the enlarged end 7 of the arcuate slot 6 in the door-supporting member F.

The inner piece or member 10 of the two-piece arm H, has a rod 17, see FIG. 5, that projects therefrom and extends in a radial direction from the pivotal support 9 for the inner piece. A coil spring 18 has one end connected to the outer end of the rod 17 and has its other end connected to a pin 19 that extends upwardly from the baseplate E. The spring 18 yieldingly urges therod 17 to swing the inner piece 10 of the articulated arm H in a counterclockwise direction about the pivot 9. This particular mechanism plus the yielding pull of the spring 15 on the outer piece 11 of the arm I-[ will cause the drive wheel L to frictionally engage with the drum M to cause it to rotate and to rotate the circular display shelves C.

I will now describe the mechanism for freeing the drive wheel L from the drum M when a person desires to open the display refrigerator door B and this will stop the shelves C from rotating and permit the person to remove one or more items from the shelves. Also, the shelves are free to be rotated by hand for bringing any desired item into a position near the open door so that the item can be readily removed. I show a solenoid N in FIG. 5 that has an armature 20, and a shank 21 extends axially beyond the outer end of the amiature and is received in a slot provided near the outer end of the rod 17. The shank 21 is threaded to receive a nut 22 that bears against the rod 17 for operatively connecting the rod to the shank.

A simple electric having is diagrammatically shown in FIG.

5 for energizing the solenoid and when a person desires to open the refrigerator door B he closes a switch 23, and this connects a source of current 24 to the solenoid N for energizing it and retracting the armature 20. The movement of the armature will cause the shank 21 to swing the rod 17 in a clockwise direction about the pivot 9 from the position shown in FIG. 5 into that shown in FIG. 6. Note in FIG. 6 that the rod 17 has swung the articulated arm H in a clockwise direction about the pin 9 and the arm has carried the drive wheel L away from the drum M. The shelving C will now stop rotating.

The same clockwise swinging of the articulated arm H, caused by the energizing of the solenoid N, will cause the inner piece or member 10 of the arm to bring the rotating drive wheel K into frictional engagement with the outer edge 25 of the arcuate slot G in the door-supporting member F. The drive wheel K is rotating in a clockwise direction and FIG. 6 shows it in frictional contact with the arcuate edge 25 and already rotating the member F to swing the arcuate door B toward open position. Since the center 5 for the door-supporting member F and for the arc of the door is spaced to the left of the shaft axis 6 when the door is closed as shown in FIG. 5, the door will be moved inwardly and away from the door opening in the refrigerator as the door is swung in a clockwise direction into open position.

The length of the outer arcuate edge 25 of the slot G in the door-supporting member F is sufiicient for the drive wheel K to entirely open the door B before the drive wheel reaches the enlarged end 8 of the arcuate slot G, see FIGS. 6 and 7. I provide novel means for holding the door B in open position so long as the switch 23 remains closed. The switch can be manually kept closed or an electric timer, not shown, may be inserted into the electrical circuit, shown in FIG. 5, for keeping the circuit closed to the solenoid N for a predetennined length of time, after which the electric circuit to the solenoid can be opened. FIGS. 5, 6 and 7 show the door-supporting member F provided with a pin 26 that extends downwardly from a spoke 27 in the member. A spring-biased arm P is pivoted at 28 to the baseplate E and a spring 29 tends to swing the arm P in a clockwise direction about its pivot. The arm carries a cam member 30 that has an inclined end. FIG. 6 shows the pin 26 on the door-supporting member F about to contact with the cam 30 as the member F is rotated in a clockwise direction.

A spring-biased pawl 31 is pivoted to the baseplate E at 32', see FIGS. 5 to 9 inclusive, and the spring, not shown, tends to rotate the pawl in a clockwise direction about its pivot. The pawl 31 is positioned on the baseplate and underlies the doorsupporting member F so that a depending pin 32 on the arm P will contact with the hooked end 33 of the pawl to swing the latter as the pin 32 is carried by the swinging arm P until the pin 32 engages and is caught by the hooked end of the pawl. The pawl will prevent the return movement of the arm P even though the clockwise rotating member F has caused its pin 26 to move beyond the outer end of the cam 30 that is carried by the arm P to free the arm, see FIG. 7. Between the two positions of movement indicated by FIGS. 6 and 7, the pin 26 on the member F has engaged with the cam 30 to swing the arm P from inoperative position in FIG. 6 into the cocked position shown in FIG. 7 where the pawl 31 prevents the immediate return movement of the spring biased arm P. The spring 29 has been tensioned by the swinging of the arm P into its cocked position.

When the door-supporting member F swings the refrigerator door B into fully open position as shown in FIG. 7, the rotating drive wheel K will have entered the enlarged end 8 of the arcuate slot G in the member and the continued rotation of the drive wheel K will have no effect on swinging the member F because the drive wheel no longer engages with the arcuate edge 25 of the slot. The door B will remain in open position so long as the switch 23, shown in FIG. 5, remains closed. As already stated, an electric timer, not shown, could be placed in the electric circuit to keep the current flowing to the solenoid N for a predetermined length of time after which the current would be cut off to the solenoid N. While the door 8 remains in open position, the drive wheel L is held out of engagement with the drum M on the vertical shaft 6 and the shelves C and shaft will stop rotating. However, a person can rotate the shelves by hand in order to bring any desired item on a shelf into a position where it may be readily removed.

As soon as the electric current to the solenoid is cut off by the opening of the switch 23, shown in FIG. 5, the solenoid N will become deenergized and the spring 18 will swing the rod 17 counterclockwise and the rod in turn will swing the inner piece of the articulated arm H to the left in FIG. 8 and about the pivot 9 to permit the outer piece 11 of the arm to move the drive wheel L into frictional engagement with the drum M. The spring 15 will yieldingly hold the drive wheel L in engagement with the drum to start the vertical shaft 6 and shelving C to rotating again.

At the same time the counterclockwise swinging of the inner piece 10 of the articulated arm l-I will move the drive wheel K into frictional contact with the inner edge 34 of the arcuate slot G in the door-supporting member F. The spring 15 permits any slight angular adjustment between the two pieces or members 10 and 11 of the articulated arm H so that the arm will hold the drive wheel L in frictional engagement with the drum M to cause it to rotate and the arm will also hold the drive wheel K in frictional contact with the arcuate edge 34 of the slot G. The drive wheel K is rotating in a clockwise direction and its engagement with the arcuate edge 34 of the slot G in the member F will start the member to rotating counterclockwise and start to swing the arcuate refrigerator door into closed position, see FIG. 8. During the greater portion of the swinging movement of the door B into closed position, the pawl 31 will engage with the pin 32 on the spring-biased arm P and hold it in cocked position, see FIGS. 8 and 9.

Due to the eccentric mounting of the door-supporting member F on the vertical shaft D, the frame of the door B will not frictionally engage with the sealing member 4 surrounding the door opening in the display refrigerator front wall 1, see FIGS. 8 and 9 until the door is at the end of its closing movement. I will now describe the auxiliary mechanism which includes the spring-biased arm P and the pawl 31 that is brought into operation just prior to the door B being completely closed so that this mechanism will apply an additional closing force on the door that is necessary to overcome any friction as the door B is brought into contact with the sealing member 4 surrounding the door opening in the front refrigerator wall 1. The door-supporting member F has a lever Q pivoted thereto at 35, see FIGS. 8, 9 and 10. The lever has a hook-shaped portion 36 at one end and a cam-shaped portion 37 at its other end. The lever is carried on the underside of the member F and lies in the same horizontal plane as occupied by the pawl 31. The lever Q has a spring to hold it in a counterclockwise tension, (not shown).

FIG. 9 shows the door B in almost closed position and the cam-shaped end 37 of the lever Q being engaged by an upstanding pin 38 that is secured to the baseplate E. The pin 38 is positioned on the baseplate so that it will engage with the cam-shaped end 37 of the lever Q just at the moment the hook-shaped end 36 of the lever just clears the pin 32 on the arm P, the hook-shaped end passing on the opposite side of the pin 32 from that occupied by the pawl 31. FIG. 9 illustrates the moment when the hook-shaped end 36 of the lever Q has just cleared the pin 32 on the arm P and the cam-shaped end 37 of the lever is being engaged by the pin 38 as the lever is moved by the rotating member F. The cam-shaped end 37 in passing by the stationary pin 38 on the baseplate E will swing the lever Q about its pivot 35 to force the hook-shaped end 36 against the opposing hook-shaped end of the pawl 31 for simultaneously disloging the pawl from the pin 32 and causing the hook-shaped end of the lever to engage with the pin 32.

It will be seen from this that the full retracting force of the spring 29 on the arm P, in trying to swing the arm in a clockwise direction about its pivot 28, will be transferred to the lever Q that now engages with the pin 32, and this force will be added to the normal closing force of the door B, created by the rotating drive wheel K frictionally engaging with the inner arcuate edge 34 of the slot G in the member F, see FIG. 9. The spring 29 is connected to the arm P at a greater distance from the pivot point 28 of the arm then is the pin 32 which is now engaged by the hook-shaped end of the lever Q. Therefore, the auxiliary force exerted by the spring 29 on the arm P will be increased because the pin 32 on the arm is at a closer point to the pivot 28 and this force will tend to move the lever Q to the right in FIG. 9 and augment the force exerted by the rotating drive wheel K in rotating the member F in a counterclockwise direction for closing the door FIG. 10 shows the pawl 31 freed from the pin 32 on the arm P and shows the hook-shaped end of the lever Q being engaged by the pin 32 so that the spring 29 is swinging the arm P clockwise about its pivot 28 will cause the lever Q to move the member F so that the door B will be moved into a closed and airtight sealing position with the door frame in the front refrigerator wall 1. It will also be noted that this auxiliary door closing force generated by the spring 29 comes into operation just as the rotating drive wheel K nears the end of its frictional engagement with the inner arcuate edge 34 of the slot G and is about to enter the enlarged end portion 7 of the slot where the drive wheel can rotate freely until the current to the electric motor is shut off. It should be noted that the baseplate E has an upstanding pin 39 so positioned that it will engage with a cam-shaped portion on the hook-shaped end 36 of the lever Q for swinging the lever clear of the pin 32 on the arm P when the door B is in closed position. The arm P is now freed from the lever so that the spring 29 can swing it back to its starting and inoperative position shown in FIG. 5. The mechanism is now ready for a repeat performance whenever a person again desires to open the door B.

I claim:

1. In combination:

a. a cabinet having a door opening therein;

b. a vertical rotatable shelf-supporting shaft mounted in said cabinet and having a drum keyed thereto c. a door carrying member rotatable on said shaft and supporting a door that can close the door opening in said cabinet; said member having an arcuate slot therein, the length of the slot being longer than the width of said door;

d. a first drive wheel frictionally engaging with said drum for rotating said shaft;

e. a second drive wheel positioned in the arcuate slot and having a diameter less than the width of said slot;

f. a motor operatively connected to both drive wheels for rotating them and causing said first drive wheel to rotate said shaft; and

g. means for removing said first drive wheel from frictional engagement with said drum and for moving said second drive wheel into frictional engagement with one side of said arcuate slot for rotating sald door support member in a direction for opening the door.

2. The combination as set forth in claim 1: and in which a. means is provided for holding the door in open position;

the arcuate slot having an enlarged portion for receiving said second drive wheel when said door reaches open position so that said second drive wheel will cease to frictionally engage with the side of said arcuate slot.

3. The combination as set forth in claim 2: and in which a. the means for removing said first drive wheel from frictional engagement with said drum can again be actuated for causing frictional engagement between the two, the

same means causing said second drive wheel to frictionally engage with the opposite side of said arcuate slot for rotating said door-supporting member in the opposite direction for closing the door.

The combination as set forth in claim 1: and in which a. said door carrying member is eccentrically mounted on said shaft so that a rotation of said member to open the door will not only rotate the door into open position, but at the same time will move the door inwardly for more quickly freeing the door from contacting with the edges of the door opening.

5. In combination:

a. a cabinet having a door opening therein;

b. a vertical rotatable shelf-supporting shaft mounted in said cabinet;

c. a door carrying a member eccentrically mounted on said shaft and supporting a door that is arcuate in shape with the center of the arc coinciding with the center of said member; said cabinet having a door opening that is arcuate in shape, the edges of the door opening coinciding with the edges of said door when the latter is in closed position, said member having an arcuate slot therein whose center coincides with the same center for the arcuate door, the length of the slot being longer than the width of said door;

d. a motor actuated drive wheel positioned in said arcuate slot and having a diameter less than the width of said slot; and

e. means for moving said drive wheel into frictional engagement with one side of said arcuate slot for rotating said door-supporting member in a direction for opening the door, the eccentric mounting of said member causing said door to move inwardly and away from the door opening for more quickly freeing the door from contacting with the edges of the door opening during the initial door opening movement.

6. The combination as set forth in claim and in which a. means is provided for holding the door in open position;

said arcuate slot having an enlarged portion for receiving said drive wheel when said door reaches open position so that said drive wheel will cease to frictionally engage with the side of said arcuate slot. 7. The combination as set forth in claim 6: and in which a. the means for moving said drive wheel into frictional engagement with one side of said arcuate slot can again be actuated for causing said drive wheel to frictionally engage with the opposite side of said arcuate slot for rotating said door-supporting member in the opposite direction for closing the door, the eccentric mounting of said door carrying member spacing the door inwardly away from the edges of the door opening until the door is practically in closed position at which time the door is moved into frictional contact with all edges of the door opening. The combination as set forth in claim 7: and in which auxiliary door closing means is automatically actuated to aid the drive wheel in rotating the door-supporting member during the last portion of rotative movement of the member to overcome the resistance developed by the edges of the door coming into contact with the adjacent edges of the door opening. In a door opening and closing mechanism: a cabinet having a door opening therein which is arcuate in horizontal section;

b. a vertical rotatable shelflsupporting shaft mounted in said cabinet;

c. a door carrying member rotatable on said shaft and supporting a door that can close the door opening in said cabinet; said member having an arcuate slot therein whose length is longer than the width of said door;

d. a motor actuated drive wheel positioned in said slot and having a diameter less than the width of said slot;

e. means for moving said drive wheel into frictional engagement with one side of said arcuate slot for rotating said door-supporting member in a direction for opening the door; I

f. an arm pivotally mounted in said cabinet and underlying said door-supporting member and a spring yieldingly urging the arm to swing in one direction; a pin carried by said door-supporting member and swinging said arm in a direction for tensioning said spring when the member rotates to open the door;

g. a spring-biased pawl pivotally mounted in said cabinet and near said arm; a pin mounted on said arm and engageable by said pawl when said arm has been swung for tensioning the arm engaging spring during the rotation of said member in a direction for opening the door; said pawl holding said arm in its spring tensioning position so long as door remains open;

h. the means for moving said drive wheel into frictional engagement with one side of said arcuate slot can again be actuated for causing said drive wheel to frictionally engage with the opposite side of said arcuate slot for rotating said door-supporting member in the opposite direction for moving the door toward closed position; and

. a spring-biased lever carried by said door-supporting member and having a hook-shaped end for engaging with the pawl and freeing it from the pin on a said arm when the door nears closed position, said hook-shaped end simultaneously engaging with the pin on said arm, whereby the tensioned spring that is attached to said arm will swing the latter in a direction for causing its pin to move said lever to act as an auxiliary force in aiding said drive wheel in rotating said door-supporting member for closing the door.

10. The combination as set forth in claim 9: and in which a. said door carrying member is eccentrically mounted on said shaft so that a rotation of said member to open the door will move the door inwardly away from the edges of the door opening for more quickly freeing the door from contacting with the edges of the door opening;

b. the eccentric mounting of the door-supporting member causing the member while closing the door, to bring the edges of the door into sealing contact with the adjacent edges of the door opening only during the last portion of the rotative movement of the member. 

1. In combination: a. a cabinet having a door opening therein; b. a vertical rotatable shelf-supporting shaft mounted in said cabinet and having a drum keyed thereto c. a door carrying member rotatable on said shaft and supporting a door that can close the door opening in said cabinet; said member having an arcuate slot therein, the length of the slot being longer than the width of said door; d. a first drive wheel frictionally engaging with said drum for rotating said shaft; e. a second drive wheel positioned in the arcuate slot and having a diameter less than the width of said slot; f. a motor operatively connected to both drive wheels for rotating them and causing said first drive wheel to rotate said shaft; and g. means for removing said first drive wheel from frictional engagement with said drum and for moving said second drive wheel into frictional engagement with one side of said arcuate slot for rotating saId door supporting member in a direction for opening the door.
 2. The combination as set forth in claim 1: and in which a. means is provided for holding the door in open position; the arcuate slot having an enlarged portion for receiving said second drive wheel when said door reaches open position so that said second drive wheel will cease to frictionally engage with the side of said arcuate slot.
 3. The combination as set forth in claim 2: and in which a. the means for removing said first drive wheel from frictional engagement with said drum can again be actuated for causing frictional engagement between the two, the same means causing said second drive wheel to frictionally engage with the opposite side of said arcuate slot for rotating said door-supporting member in the opposite direction for closing the door.
 4. The combination as set forth in claim 1: and in which a. said door carrying member is eccentrically mounted on said shaft so that a rotation of said member to open the door will not only rotate the door into open position, but at the same time will move the door inwardly for more quickly freeing the door from contacting with the edges of the door opening.
 5. In combination: a. a cabinet having a door opening therein; b. a vertical rotatable shelf-supporting shaft mounted in said cabinet; c. a door carrying member eccentrically mounted on said shaft and supporting a door that is arcuate in shape with the center of the arc coinciding with the center of said member; said cabinet having a door opening that is arcuate in shape, the edges of the door opening coinciding with the edges of said door when the latter is in closed position; said member having an arcuate slot therein whose center coincides with the same center for the arcuate door, the length of the slot being longer than the width of said door; d. a motor actuated drive wheel positioned in said arcuate slot and having a diameter less than the width of said slot; and e. means for moving said drive wheel into frictional engagement with one side of said arcuate slot for rotating said door-supporting member in a direction for opening the door, the eccentric mounting of said member causing said door to move inwardly and away from the door opening for more quickly freeing the door from contacting with the edges of the door opening during tHe initial door opening movement.
 6. The combination as set forth in claim 5: and in which a. means is provided for holding the door in open position; said arcuate slot having an enlarged portion for receiving said drive wheel when said door reaches open position so that said drive wheel will cease to frictionally engage with the side of said arcuate slot.
 7. The combination as set forth in claim 6: and in which a. the means for moving said drive wheel into frictional engagement with one side of said arcuate slot can again be actuated for causing said drive wheel to frictionally engage with the opposite side of said arcuate slot for rotating said door-supporting member in the opposite direction for closing the door, the eccentric mounting of said door carrying member spacing the door inwardly away from the edges of the door opening until the door is practically in closed position at which time the door is moved into frictional contact with all edges of the door opening.
 8. The combination as set forth in claim 7: and in which a. auxiliary door closing means is automatically actuated to aid the drive wheel in rotating the door-supporting member during the last portion of rotative movement of the member to overcome the resistance developed by the edges of the door coming into contact with the adjacent edges of the door opening.
 9. In a door opening and closing mechanism: a. a cabinet having a door opening therein which is arcuate in horizontal section; b. a vertical rotatable shelf-supporting shaft mounted in said cabinet; c. a door carrying member rotatable on said shaft and supporting a door that can close the door opening in said cabinet; said member having an arcuate slot therein whose length is longer than the width of said door; d. a motor actuated drive wheel positioned in said slot and having a diameter less than the width of said slot; e. means for moving said drive wheel into frictional engagement with one side of said arcuate slot for rotating said door-supporting member in a direction for opening the door; f. an arm pivotally mounted in said cabinet and underlying said door-supporting member and a spring yieldingly urging the arm to swing in one direction; a pin carried by said door-supporting member and swinging said arm in a direction for tensioning said spring when the member rotates to open the door; g. a spring-biased pawl pivotally mounted in said cabinet and near said arm; a pin mounted on said arm and engageable by said pawl when said arm has been swung for tensioning the arm engaging spring during the rotation of said member in a direction for opening the door; said pawl holding said arm in its spring tensioning position so long as said door remains open; h. the means for moving said drive wheel into frictional engagement with one side of said arcuate slot can again be actuated for causing said drive wheel to frictionally engage with the opposite side of said arcuate slot for rotating said door-supporting member in the opposite direction for moving the door toward closed position; and i. a spring-biased lever carried by said door-supporting member and having a hook-shaped end for engaging with the pawl and freeing it from the pin on a said arm when the door nears closed position, said hook-shaped end simultaneously engaging with the pin on said arm, whereby the tensioned spring that is attached to said arm will swing the latter in a direction for causing its pin to move said lever to act as an auxiliary force in aiding said drive wheel in rotating said door-supporting member for closing the door.
 10. The combination as set forth in claim 9: and in which a. said door carrying member is eccentrically mounted on said shaft so that a rotation of said member to open the door will move the door inwardly away from the edges of the door opening for more quickly freeing the door from contacting with the edges of the door opening; b. the eccentric mounting of the door-supporting memBer causing the member while closing the door, to bring the edges of the door into sealing contact with the adjacent edges of the door opening only during the last portion of the rotative movement of the member. 